Tests RYZ101 in advanced ER-positive, HER2-negative breast cancer
Tests RYZ101, a radiation-carrying drug, in people with advanced breast cancer.
Plain-language title generated from the registry record
Registry title: Trial of 225Ac-DOTATATE (RYZ101) in Subjects With ER+, HER2-negative Unresectable or Metastatic Breast Cancer Expressing SSTRs.
Key facts
- Where
- Québec, Toronto, and Victoria, CanadaSee the 3 sites
- Phase
- Phase 1/2
Where in Canada
- QuébecQuébec, CanadaNot yet recruiting
- TorontoToronto, CanadaNot yet recruiting
- VictoriaVictoria, CanadaNot yet recruiting
Questions to ask the study team
- How often do I need to come in, and for how long each time?
- Are travel costs paid?
- Can I keep my own doctor?
- What happens if I want to stop?
Trial details
- Who runs it
- RayzeBio, Inc.
- Trial code
- NCT06590857
- Record updated
- 6 October 2026
- Original description
Phase 1b/2 open-label trial of 225Ac-DOTATATE (RYZ101) in subjects with ER+, HER2-negative unresectable or metastatic breast cancer expressing SSTRs.Read full original descriptionShow less
Phase 1b/2 Open-label Trial of 225Ac-DOTATATE (RYZ101) in Subjects With Estrogen Receptor-positive (ER+), Human Epidermal Growth Factor Receptor 2 (HER2)-Negative, Locally Advanced and Unresectable or Metastatic Breast Cancer Expressing Somatostatin Receptors (SSTRs) (TRACY-1).
Phase 1b/2 open-label trial of 225Ac-DOTATATE (RYZ101) in subjects with ER+, HER2-negative unresectable or metastatic breast cancer expressing SSTRs.
Inclusion: Subjects must meet all the following criteria for enrollment in the study:; Histologically confirmed, ER+, HER2-negative, locally advanced and unresectable or metastatic breast cancer not amenable to treatment with curative intent; Adequate renal, hematologic, and hepatic function; Additional inclusion criteria for Monotherapy arm:; Measurable disease with at least 80% SSTR-positive lesions by SSTR-PET imaging; Eastern Cooperative Oncology Group (ECOG) performance status ≤2; Documented radiologic progression after at least 2 and no more than 4 prior chemotherapy or ADC regimens in the metastatic setting; Additional inclusion criteria for ET Combination arms:; Prior treatment with CDK4/6 inhibitors in combination with endocrine therapy in the advanced or metastatic setting; Eastern Cooperative Oncology Group (ECOG) performance status ≤1; Bone only or bone dominant disease. At least 1 bone lesion must be SSTR-positive on SSTR-PET imaging. For bone dominant disease, at least 50% of soft tissue measurable lesions must be SSTR-positive on SSTR-PET imaging. At least one bone lesion must be positive on both SSTR-PET and on FDG-PET imaging; Brain metastases are allowed if definitively treated and clinically stable as confirmed by interval imaging.
Exclusion: Prior radiopharmaceutical therapy, including radioembolization; Any toxicities from prior treatments that have not recovered to CTCAE Grade ≤1, except for alopecia; Prior or concurrent malignancy whose natural history or treatment has the potential to interfere with the study safety or efficacy assessments; Additional exclusion criteria for ET Combination arms:; Presence of liver metastases or symptomatic metastatic visceral disease; Prior PARPi exposure or are candidates for PARPi per local guidelines; Significant cardiovascular disease; Known active uncontrolled or symptomatic central nervous system (CNS) metastases, carcinomatous meningitis, spinal cord compression, or leptomeningeal disease; History of hypersensitivity or allergy to 225Ac, 68Ga, 64Cu, octreotate, or any of the excipients of DOTATATE imaging agents; Subjects who meet any of the following criteria will be excluded from the study:; Pregnancy or breastfeeding.